Many apparatuses and methods are known for cleaning carpeting and other flooring, wall and upholstery surfaces. The cleaning apparatuses and methods most commonly used today apply cleaning fluid as a spray under pressure to the surface whereupon the cleaning fluid dissolves the dirt and stains and the apparatus scrubs the fibers while simultaneously applying a vacuum or negative pressure to extract the cleaning fluid and the dissolved soil. Although such relatively high pressure methods are the most commonly used, they have disadvantages. First, the majority of the soil is at or near the surface of the fibers so that high pressure cleaning tends to drive some of the surface soil and cleaning fluid deeper, whereby a very powerful vacuum system is required to extract particles that have been driven beneath the outermost surface. Furthermore, the use of cleaning fluid under pressure, applied as a spray through conventional jets, drives the fluid itself deeper, and the fluid that is not immediately removed by the vacuum source requires a significantly longer drying period. While longer drying time is an inconvenience, if the carpeting is used prior to its being completely dry, it is more likely to become soiled. Additionally, conventional jets atomize the sprayed fluid which then comes into contact with the air, causing significant heat loss and diminishing the cleaning power of the fluid.
Many different apparatuses and methods for spraying cleaning fluid under pressure and then removing it with a vacuum are illustrated in the prior art supplied herewith but will not be discussed in detail.
Another category of carpeting and upholstery cleaning apparatuses and methods use a rotating device wherein the entire machine is transported over the carpeting while a cleaning head is rotated about a vertical axis. Typically, these machines include a plurality of arms, each of having one or more spray nozzles or a vacuum source providing a more intense scrubbing action since, in general, more scrubbing surfaces contact the carpet. These apparatuses and methods are primarily illustrated in U.S. Pat. No. 4,441,229 granted to Monson on Apr. 10, 1984, and are listed in the prior art known to the inventor but not discussed in detail herein.
A third category of carpeting and upholstery cleaning apparatuses and methods that attempt to deflect or otherwise control the cleaning fluid are illustrated by U.S. Pat. No. 4,137,600 granted to Albishausen on Feb. 6, 1970, which discloses a cleaning apparatus wherein the cleaning fluid is changed into a liquid curtain by a baffle within the cleaning head; U.S. Pat. No. 4,335,486 granted to Kochte on Jan. 22, 1982, which discloses a surface cleaning machine wherein the cleaning fluid is deposited upon the surface of the carpet pile from a wick like device wetted with the cleaning fluid; U.S. Pat. No. 4,649,594 granted to Grave on Mar. 17, 1987, which discloses a cleaning head wherein the cleaning solution is sprayed through a narrow passage and some is wicked along the surface of the passage; U.S. Pat. No. 5,157,805 granted to Pinter on Oct. 27, 1992, which discloses a method and apparatus for cleaning a carpet wherein the cleaning fluid is sprayed by nozzle against the back of a striker plate and then flows downwardly and through the carpet to a pickup vacuum; and U.S. Pat. No. 5,561,884 granted to Nijland et al on Oct. 8, 1996, which discloses a suction attachment spray member wherein the fluid is sprayed against a distributor plate that creates a planar diverging liquid jet substantially filling the vacuum chamber.
U.S. Pat. No. 6,243,914, which was granted Jun. 12, 2001, to the inventor of the present patent application and which is incorporated herein by reference, discloses a cleaning head for carpets, walls or upholstery, having a rigid open-bottomed main body that defines a surface subjected to the cleaning process. Mounted within or adjacent to the main body and coplanar with the bottom thereof is a fluid-applying device which includes a slot at an acute angle to the plane of the bottom of the body located adjacent the plane of the bottom of the body, the slot configured such that the fluid is applied in a thin sheet that flows out of the slot and into the upper portion of the surface to be cleaned and subsequently into the vacuum source for recovery. The cleaning head is alternatively multiply embodied in a plurality of arms which are rotated about a hub.
FIG. 1 is a cross-sectional view that illustrates one of four separate embodiments of the cleaning head disclosed in U.S. Pat. No. 6,243,914 wherein the cleaning head 1 for applying cleaning fluid without the inherent problems of spray either escaping or unduly penetrating the carpeting. Front and back surfaces 3, 5 of the cleaning head 1 combine with opposing end panels (not shown) to define a rectangular lip 7 which defines a surface contact area of the surface to be cleaned, which is momentarily subjected to the cleaning environment generated by the cleaning head 1. Securely mounted to an interior portion of the cleaning head 1 is a downwardly open fluid supply chamber 9 formed between a first wall 11 terminating in a head surface 13 and a second wall 15 terminating in an inwardly turned foot 17. The fluid supply chamber 9 terminates in an angled slot or groove 19 adjacent to the head surface 13 and oriented at an obtuse angle thereto, i.e., an acute angle to the surface to be cleaned. Walls 21 and 23 combine with opposing end panels (not shown) to form a vacuum chamber 25 that is spaced away from the fluid supply chamber 9 by the width of the head surface 13.
As disclosed in U.S. Pat. No. 6,243,914, cleaning fluid is supplied in a steady stream downwardly through the fluid supply chamber 9 between the walls 11 and 15 and flows outwardly through the angled slot 19 past the foot 17 and is drawn in a sheet across the head surface 13 by a vacuum formed in the vacuum chamber 25, whereby it is applied uniformly to the carpeting or other surface to be cleaned. The fluid is removed from the cleaned surface by vacuum in the vacuum chamber 25. The utilization of a sheet of fluid which flows down the fluid supply chamber 9 and across the head surface 13 eliminates the cooling of the fluid that results from atomizing caused by prior art spray nozzles. The utilization of a sheet of fluid also reduces the amount of fluid being used for a given cleaning job, and eliminates over spray of the cleaning fluid should the cleaning head 1 be inadvertently moved from the surface to be cleaned or tilted so one edge is raised.
However, it is generally understood in the art that improvements are needed in reducing the quantity of cleaning fluid driven by the cleaning apparatus beneath the outermost surface and the residual cleaning fluid left on the outermost surface by the cleaning head is desirable.
U.S. Pat. No. 7,070,662, which was granted Jul. 4, 2006, to the inventor of the present patent application and which is incorporated herein by reference, discloses improvements to the cleaning head disclosed in U.S. Pat. No. 6,243,914. According to U.S. Pat. No. 7,070,662 a bar jet assembly which improves the functioning of the cleaning head by reducing the residual cleaning fluid left on the outermost surface by the cleaning head.
Furthermore, it is generally understood in the art that uniform application of cleaning fluid to the surface is critical for ensuring uniform cleaning in a single pass. Such uniform application of cleaning fluid is not important given the cleaning head disclosed in U.S. Pat. No. 6,243,914 and the bar jet assembly improvements disclosed in U.S. Pat. No. 7,070,662 are utilized in combination with a rotary cleaning plate that is coupled for high speed rotary motion.
As illustrated in FIG. 2, the cleaning head disclosed in U.S. Pat. No. 7,070,662, includes a substantially circular rotary cleaning plate 31 having a cleaning fluid distribution manifold 33 including a central sprue hole 35 for receiving the pressurized cleaning fluid and an expansion chamber 37 for reducing the pressure of the cleaning fluid to below a delivery pressure provided by a source of pressurized cleaning fluid. Expansion chamber 37 is connected for distributing the liquid cleaning fluid outward along closed liquid cleaning fluid distribution channels 39 to application by a plurality of bar jet assemblies 41 uniformly distributed across the bottom cleaning surface of the rotary cleaning plate 31. Each of the bar jet assemblies 41 includes a cleaning fluid discharge slot or groove 43 adjacent to a fluid retrieval slot 45 coupled to a vacuum source for retrieving a quantity of soiled cleaning fluid.
As indicated by the rotational arrow in FIG. 2, the rotary cleaning plate 31 is rotated at high speed during application of cleaning fluid to the target surface. The rotary cleaning plate 31 successfully delivers a generally uniform distribution of cleaning fluid to a target surface between the quantity of bar jet assemblies 41 and the large number of passes of each bar jet assembly 41 occasioned by the high speed rotary motion of the cleaning plate 31 regardless of any lack of uniformity in the instantaneous fluid delivery of any individual bar jet assembly 41. Additionally, the instantaneous fluid delivery of each individual bar jet assembly 41 tends to be generally uniform at least because the length of the bar jet is minimal as compared with the size of the rotary cleaning plate 31.
However, it is generally understood that, by the laws of hydrodynamics, it is generally difficult to provide a uniform distribution of pressurized cleaning fluid along a discharge slot or groove of an extended length.